1. Field of the Invention
The present invention relates generally to livestock handling equipment and, more particularly, to a cutter gate apparatus for automatically identifying and sorting livestock as they walk through the apparatus.
2. Discussion of the Prior Art
It is known to provide a cutter gate apparatus in a daily operation for identifying dairy cows as they leave the milking parlor and sorting them so that selected cows can receive special handling such as periodic medical treatment or the like. The conventional apparatus includes an elongated alley having a first end presenting an entrance and a second end presenting a main exit and a sort exit. An air-driven gate is positioned in the second end of the alley for movement between a sorting position in which the gate blocks the main exit and opens the sort exit, and a non-sorting position in which the gate opens the main exit and closes the sort exit. A pneumatic circuit is provided for actuating the gate and includes an air-driven spool valve for controlling operation of the gate.
An electronic identification system such as that disclosed in U.S. Pat. No. 4,798,175, is provided along the alley for sensing the presence of livestock in the alley and providing an electrical signal when an animal to be sorted is present. An antenna is supported on a curtain that is draped over the alley at a position intermediate the ends, and each animal to be identified by the system wears a transponder that can be detected when the animal passes the antenna. When an animal to be sorted is detected by the identification system, an electrical signal is produced that interfaces with the pneumatic circuit to generate a fluid signal that triggers the spool valve to move the gate to the sorting position.
A one-way gate is provided in the sort exit and includes a pneumatic switch that is actuated when an animal pushes the one-way gate out of the way upon passing through the sort exit. The pneumatic signal from the switch is delivered to the spool valve to move the gate back to the non-sorting position. Thus, the means used to control movement of the gate is completely pneumatic, including the air-driven spool valve, the pneumatic limit switch on the one-way gate, and the interface between the pneumatic spool valve and the electronic identification system.